We all have many phases to our lives. First we are children, learning from our parents. Then we are teenagers, rebelling against our parents. Next we are on our own working or in college. Our lives grow more complicated as we marry and have families of our own. Soon our children are grown and gone and our life moves on to another phase.
So it is with writing. As we grow and learn in life, our writing grows and changes. After digging out some old novels I wrote years ago, I was amazed at the changes in my writing. Hopefully, I am a much better writer than I was twenty years ago, but I know my themes and writing style has changed.